The retina is a delicate neural tissue lining the back of the eye that converts light stimuli into electric signals for processing by the brain. Within the eye, the retina is disposed upon underlying retinal pigment epithelium and choroid, which provide the retina with a supply of blood and nutrients. A common and potentially blinding condition known as retinal detachment occurs when the retina becomes disassociated from its underlying retinal pigment epithelium and/or choroid with the accumulation of fluid in the intervening space. The loss of visual function appears to be more pronounced when the retinal detachments involve the central macula.
Photoreceptor death after retinal detachment (“RD”) is a major cause of permanent visual loss in various ocular diseases. During retinal detachment, the entire retina or a portion of the retina becomes dissociated from the underlying retinal pigment epithelium and choroid. As a result, the sensitive photoreceptor cells disposed in the detached portion of the retina become deprived of their normal supply of blood and nutrients. If untreated, the retina or, more particularly, the sensitive photoreceptor cells disposed within the retina die causing partial or even complete blindness. Physical separation of photoreceptors from the underlying retinal pigment epithelium occurs in age-related macular degeneration (Dunaief J L et al. (2002) ARCH. OPHTHALMOL. 120:1435-1442), diabetic retinopathy (Barber A J et al. (1998) J. CLIN. INVEST. 102:783-791), retinopathy of prematurity (Fulton A B et al. (2001) ARCH. OPHTHALMOL. 119:499-505), as well as rhegmatogenous (caused by a break in the retina) retinal detachment (Cook B et al. (1995) INVEST. OPHTHALMOL. VIS. SCI. 36:990-996, Arroyo J G et al. D F (2005) AM. J. OPHTHALMOL. 139:605-610). Although surgery may be carried out to reattach the retina, only two-fifths of patients with rhegmatogenous retinal detachment involving the macula, a region essential for central vision, recover 20/40 or better vision due to photoreceptor death (Arroyo et al. (2005) J. OPHTHALMOL. 139:605-610; Campo et al. (1999) OPHTHALMOLOGY 106-1811-1815). In other retinal disorders including age-related macular degeneration and diabetic retinopathy, retinal photoreceptor detachment persists chronically and vision loss progresses for many patients. Studies in humans and in experimental animal models have demonstrated that after detachment of the retina, the photoreceptors begin to degenerate and die over time. Identification of the mechanisms that underlie photoreceptor death is critical to developing new treatment strategies for these diseases.
There is still an ongoing need to minimize or eliminate photoreceptor cell death during retinal detachment. It is contemplated that minimizing photoreceptor cell death will reduce the loss of vision or the loss of visual acuity associated with retinal detachment.